As illustrated in FIG. 1, a cellular communication system generally includes a User Equipment (UE), a radio access network and a core network.
Particularly an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) is a radio access network including (evolved) Node Bs (eNBs) connected with each other. An Evolved Packet Core (EPC) is a core network system including a Home Subscriber Server (HSS), a Mobility Management Entity (MME) and a Gateway (GW), where the HSS is configured to store subscription data of subscribers, the MME is configured to perform mobility management on a UE, and the gateway is configured to perform functions of storing, forwarding and routing user plane data of the UE.
In an existing cellular communication system, in a scenario where a user application accesses a user service network, the user application can only access an application service network (including an operator, services and the Internet) over a data transmission channel set up by a UE after the UE accesses the cellular network and a proxy function provided by a core network gateway.
In a scenario where UEs communicate with each other, the UEs have to communicate with each other through relay and proxy functions provided by an eNB and a gateway, and the existing cellular communication system doesn't support such a function that service information is obtained by the UEs for proximity awareness between them.
If the Device to Device (D2D) technology is introduced into the cellular network, then various service instances can be available so that one of the UEs can obtain service information directly from the other UE through D2D communication between the UEs, and this will impose a revolutionary influence upon the existing service model of the cellular communication system, that is, the introduction of the D2D technology will come with the possibility of various new service patterns.
However the integration of the D2D technology with application services has been just conceptually developed and there has been absent a solution to have them combined so far.